Construction industry, traditionally afflicted with costs, safety concerns and material scarcity, is taking inspiration from the manufacturing industry in order to increase precision, speed and efficiency of built products. Contemporary achievements in automation and robotics allow fabrication processes to be implemented in construction strategies, while cognitive and computer sciences are suggesting collective behaviour principles as robust and effective approach to complex problem solving. Here we present a construction method that makes use of ground mobile robots to fabricate earth structures from in-situ available granular material through the deposition of soil viscous paste, a medium that, with the employment of specific digital tools, provides flexibility, ease of manipulation and sustainable applications.